#include <stdio.h>
#include <ctype.h>

int main(void)
{
	char c;
	printf("input something\n");
	scanf("%c",&c);
	if(isalpha(c))
	{
		printf("c is a alpha\n");
		if(isupper(c))
		{
			printf("c is upper\n");
			printf("tolower(%c) = %c\n",c,tolower(c));
		}
		else if(islower(c))
		{
			printf("c is lower\n");
			printf("toupper(%c) = %c\n",c,toupper(c));
		}	
	}
	else if(isdigit(c))
	{
		printf("c is a digit\n");
	}
	
	return 0;
}
